package string;

import common.Charset;

import java.io.UnsupportedEncodingException;

/**
 * Description: string charset
 * Created by 4790K_NSL on 2017/5/7.
 */
public class UtilStringChartset {


    /** 将字符编码转换成US-ASCII码     */
    static public String toASCII(String str) throws UnsupportedEncodingException {
        return changeCharset(str, Charset.US_ASCII);
    }

    /** 将字符编码转换成ISO-8859-1     */
    static public String toISO_8859_1(String str) throws UnsupportedEncodingException {
        return changeCharset(str, Charset.ISO_8859_1);
    }

    /** 将字符编码转换成UTF-8     */
    static public String toUTF_8(String str) throws UnsupportedEncodingException {
        return changeCharset(str, Charset.UTF_8);
    }

    /** 将字符编码转换成UTF-16BE     */
    static public String toUTF_16BE(String str) throws UnsupportedEncodingException{
        return changeCharset(str, Charset.UTF_16BE);
    }

    /** 将字符编码转换成UTF-16LE     */
    static public String toUTF_16LE(String str) throws UnsupportedEncodingException {
        return changeCharset(str, Charset.UTF_16LE);
    }

    /** 将字符编码转换成UTF-16     */
    static public String toUTF_16(String str) throws UnsupportedEncodingException {
        return changeCharset(str, Charset.UTF_16);
    }

    /** 将字符编码转换成GBK     */
    static public String toGBK(String str) throws UnsupportedEncodingException {
        return changeCharset(str, Charset.GBK);
    }

    /** 将字符编码转换成GB2312     */
    static public String toGB2312(String str) throws UnsupportedEncodingException {
        return changeCharset(str, Charset.GB2312);
    }

    /**
     * 字符串编码转换的实现方法
     * @param str    待转换的字符串
     * @param newCharset    目标编码
     */
    static public String changeCharset(String str, String newCharset) throws UnsupportedEncodingException {
        if(str != null) {
            //用默认字符编码解码字符串。与系统相关，中文windows默认为GB2312
            byte[] bs = str.getBytes();
            return new String(bs, newCharset);    //用新的字符编码生成字符串
        }
        return null;
    }

    /**
     * 字符串编码转换的实现方法
     * @param str    待转换的字符串
     * @param oldCharset    源字符集
     * @param newCharset    目标字符集
     */
    static public String changeCharset(String str, String oldCharset, String newCharset) throws UnsupportedEncodingException {
        if(str != null) {
            //用源字符编码解码字符串
            byte[] bs = str.getBytes(oldCharset);
            return new String(bs, newCharset);
        }
        return null;
    }

    public static void main(String[] args) throws UnsupportedEncodingException {
        UtilStringChartset test = new UtilStringChartset();
        String str = "This is a 中文的 String!";
        System.out.println("str：" + str);

        String gbk = test.toGBK(str);
        System.out.println("转换成GBK码：" + gbk);
        System.out.println();

        String ascii = test.toASCII(str);
        System.out.println("转换成US-ASCII：" + ascii);
        System.out.println();

        String iso88591 = test.toISO_8859_1(str);
        System.out.println("转换成ISO-8859-1码：" + iso88591);
        System.out.println();

        gbk = test.changeCharset(iso88591, Charset.ISO_8859_1, Charset.GBK);
        System.out.println("再把ISO-8859-1码的字符串转换成GBK码：" + gbk);
        System.out.println();

        String utf8 = test.toUTF_8(str);
        System.out.println();
        System.out.println("转换成UTF-8码：" + utf8);
        String utf16be = test.toUTF_16BE(str);
        System.out.println("转换成UTF-16BE码：" + utf16be);
        gbk = test.changeCharset(utf16be, Charset.UTF_16BE, Charset.GBK);
        System.out.println("再把UTF-16BE编码的字符转换成GBK码：" + gbk);
        System.out.println();

        String utf16le = test.toUTF_16LE(str);
        System.out.println("转换成UTF-16LE码：" + utf16le);
        gbk = test.changeCharset(utf16le, Charset.UTF_16LE, Charset.GBK);
        System.out.println("再把UTF-16LE编码的字符串转换成GBK码：" + gbk);
        System.out.println();

        String utf16 = test.toUTF_16(str);
        System.out.println("转换成UTF-16码：" + utf16);
        String gb2312 = test.changeCharset(utf16, Charset.UTF_16, Charset.GB2312);
        System.out.println("再把UTF-16编码的字符串转换成GB2312码：" + gb2312);
    }
}
